For those bassist here that want that upright sound, try a fretless bass. You will be amazed at the difference in sound. Can't afford a fretless bass? No problem, just buy a fretless neck and bolt that puppy on. You can even get them with markers to show where the frets were to help you with the intonation.
The one drawback here is that if you are using roundwound strings, they will eat the neck up. I have to have my fingerboards redone with ebony about once a year, but I feel that it is worth it. I have a '63 Fender Jazz bass and a Pedulla that I play fretless, the sound is fantastic.
SWR is coming out with a little amp this month that looks like it will be perfect for playing those little acoustic gigs

My son plays bass. We took one of his and removed the frets, sanded the fretboard smooth with a block, filled the fret slots with wood putty, and after sandibg that out, we put a coat or two of tongue oil on the fretboard. Easy job, and boy does it sound great! Also, the wood putty shows where the frets were, so it helps him in getting a feel for where the notes are.

He plays the heck out of it (with roundwounds), and I haven't noticed any appreciable wear yet, but I do understand that it will eat it up in time.

It's an easy and cheap way to make a bass fretless, and I can tell you it plays and sounds VERY good.

[updated:LAST EDITED ON Dec-20-03 AT 02:16 PM (EST)]Before any of you go ripping frets off your electric, make sure the neck is in good shape; The minimal buzz a fret will give a slightly warped neck will be greatly exaggerated when the actual fret is gone, making the bass unusable...I would go with NSH's suggestion and replace the actual neck. (Hey we're agreeing on something!)

[updated:LAST EDITED ON Jun-21-05 AT 09:16 PM (EST)] I have fretless basses ( and an upright ), but really get better results out of my old fretted precision with tapewound strings, foam under the bridge, and side-of-the-index-finger technique. Mostly though, I just play my `51 Kay C-1 with guts.
I hope this little post will serve for an introduction.